3.1 Introduction

3.1.1 General

(1) This chapter outlines the following for road and transport infrastructure:

(a) design and construction standards;

(b) advice about satisfying assessment benchmarks in the planning scheme;

(c) the information that the Council may request to be supplied for a development application.

(2) The purpose of the design standards and specifications identified in this chapter is to ensure that roads and transport infrastructure are designed and constructed to adequately provide for, where appropriate:

(f) accommodation of the largest service vehicle likely to access the site;

(g) aesthetics, improved liveability and economic growth;

(h) amelioration of noise and other pollution;

(i) a low maintenance asset for Council.

(3) This chapter provides the acceptable outcome for development within the road reserve.

(4) Deviations from or modifications to the design standards set out in this chapter may be acceptable, however it is the responsibility of the applicant to demonstrate that the proposal meets the performance outcomes of the applicable code.

(5) All work within the road reserve requires a Council permit.

(6) Some existing parts of the freight network might not comply with all of the current specified design standards.

3.1.2 Application

(1) The design standards stated in this chapter apply to development that requires:

(a) new roads and transport infrastructure;

(b) upgrades to existing roads and infrastructure that are reasonable and relevant to the plans for upgrades and the expected impact of the proposed development.

(2) The design standards identified by the road hierarchy may be modified or augmented by the design requirements of the freight, public transport, bicycle or streetscape networks.

(3) In addition to this planning scheme policy, road corridors are planned, designed and constructed in accordance with the current edition of the following:

3.2.3 Design standards

(1) Table 3.2.3.A provides a summary of the design standards for major roads. Pavement design requirements for major roads are detailed in section 3.5.

(2) Parts of the existing road network might not comply with all of the current specified design standards.

Note—The majority of motorways and some arterial roads in the local government area are owned and managed by the Queensland Government and are not covered by these road design requirements. Refer to Chapter 2 of this planning scheme policy.

3.2.4 Cross-section for major roads standards

3.2.4.1 General

(1) This section outlines additional design standards for instances where modification of the design standards in Table 3.2.3.A may be appropriate.

(2) The cross-section elements include:

(a) traffic lanes;

(b) verges;

(c) roadside drainage;

(d) medians;

(e) bicycle lanes;

(f) bus provision;

(g) on-street parking;

(h) bus stops;

(i) auxiliary lanes;

(j) pavement taper.

(3) When, as an outcome of development, only part of the ultimate design is constructed (such as one carriageway of a future dual carriageway, or an upgrading of a section of existing road), the interim cross-section provides for all road users. Bicycle, pedestrian and public transport facilities are incorporated into the partial design.

3.2.4.2 Traffic lanes

(1) Minimum traffic lane widths for both vehicles are provided in accordance with Table 3.2.3.A. Additional width may be required to achieve lateral clearances specified in either the Manual of Uniform Traffic Control Devices (Queensland) or Austroads.

(2) Sealed shoulders of 1.5m are required where no kerb exists.

(3) Sealed shoulders are constructed with a smooth surface flush with the vehicular lanes.

3.2.4.3 Roadside drainage

(1) Opportunities for including water sensitive urban design principles into the design of the road network must be maximised.

(2) Water sensitive urban design sections that incorporate swales are shown on BSD-8301.

(4) Mountable type kerb (BSD-2001) is used in medians and traffic islands.

(5) The existing ultimate alignment of the kerb and channel may not be known until a road survey is undertaken, which should extend a minimum of 50m along the road beyond the frontage of the development site and a minimum of 5m onto the adjacent land to determine the alignment for kerb and channel and the extent of cut and fill batters.

(6) The longitudinal grade of kerb and channel should not be less than 1V: 250H. To reduce the length of possible pondage in the channel, the vertical radii should be limited to a maximum of 3000m for crest curves and 1250m for sag curves.

(7) Underbed edges, which are preferred in non-urban environments, usually require table drains and wider verges than in kerbed/underground drainage situations.

In general, coloured surface, exposed aggregate, broomed concrete, or stencilled concrete treatments are preferred to paver bricks, due to maintenance considerations. Refer to Reference Specification for Civil Engineering Works S155 Road Pavement Markings for approved surface colours. Turfed and landscaped medians should have side drains installed under the median kerb (i.e. on both sides of the median). An outlet should be provided for these side drains to an existing maintenance hole, gully or other functional side drain.

3.2.4.5 Bicycle lanes

On-carriageway bicycle lanes are required on all major roads. Further information is provided in section 3.5 of this planning scheme policy.

3.2.4.6 Bus provision

(1) The major road network is designed to accommodate buses, which may include indented bus bays, transit lanes, dedicated bus lanes and priority treatment at intersections.

3.2.4.7 Bus stops

(1) Bus stops on arterial and suburban roads are located in indented bays designed to accommodate a 14.5m bus in all circumstances. The design of indented bus bays is provided in BSD-2101 and BSD-2102.

(2) Bus stops on district roads that are located within the kerbside parking lane and are to accommodate a 14.5m bus in all circumstances. The design of the bus stop is provided in BSD-2104.

(3) At locations where a parking lane is not provided, the bus stop is to be indented as per BSD-2101 and BSD-2102.

(4) Bus stops are located in the vicinity of intersections (preferably on the departure side) to enable pedestrians to cross major roads at signalised intersections.

3.2.4.10 Pavement taper

(1) If pavement widening is required on the road frontage of a development site and the road is not constructed to the ultimate width, a pavement taper is required.

(2) The pavement taper is to be a minimum of 1V:10H as a transition between the new and existing pavements of differing width.

(3) The pavement taper is to start at the lot boundary and extend away from the lot.

(4) A tapering of pavement is not permitted in tight curves.

(5) A longer taper is required at locations such as intersections and merge lanes to facilitate traffic operations.

3.2.5 Road alignment for major roads

3.2.5.1 Horizontal alignment

(1) In urban areas, constraints may dictate the adoption of adverse crossfall, which would require larger radius curves to compensate.

(2) At intersections, through lane alignments should be straight. If a curve is unavoidable, it must not start within an intersection.

(3) The speed value of a curve, as suggested by its geometry, may not be achieved because of the restriction of stopping sightlines by lateral obstructions. Where the angle of deflection is small, significantly larger radius must be used to achieve an adequate curve length and avoid kinks. It is the radii achieved for the through lanes, not for the design centre-line, which is important.

(4) In reverse curve situations:

(a) a length of the tangent between the curves is used to improve driveability and aesthetics;

(b) curves must be of a similar radius;

(c) broken back or compound curves, the radius of the second curve must not be less than that of the first;

(d) these or higher standards are applied to deviations of through lanes which result from the introduction of turn lanes.

(5) Where a reduction in the number of lanes is proposed:

(a) tapers appropriate for the design speed are to be provided for the terminating lane;

(b) tapers are located to provide merging vehicles with good visibility of the traffic stream that is being entered and facilitate safe and effective merging;

(c) the preferred location for terminating the lane is the outside of a curve;

(d) in a multi-lane situation, the dropping of the right hand lane is not acceptable.

3.2.5.2 Vertical alignment

(1) Sag vertical curves have smaller radii, based on comfort and aesthetic criteria.

(2) It is desirable, if possible, to coordinate vertical curves with horizontal.

(4) The consideration of intersection-specific sight distance requirements influence the vertical alignment adopted for the major road carriageway.

3.2.6 Intersections for major roads

3.2.6.1 General

(1) To match mid-block capacity, intersection flaring (i.e. by the addition of left and right turn lanes and in some cases, through lanes) is to be used on major roads.

(2) Right turn lanes are offset from through lanes, where possible.

(3) On the major road network, all turning movements are available.

(4) Intersections on bus routes are designed to accommodate bus turning path templates.

3.2.6.2 Signalised intersections

(1) Separate lanes are provided for left turn movements on major roads (i.e. slip lanes).

(2) In the vicinity of uses generating high pedestrian volumes (e.g. shopping centres and schools), slip lanes are not preferred and signalisation of pedestrian movement should be considered.

(3) Single stage pedestrian crosswalks are provided across all legs of a signalised intersection.

(4) Detailed design requirements for signals are provided in the BSD-4000 series.

(5) Further information regarding electrical and communications associated with signalised intersections is provided in Chapter 9 of this planning scheme policy.

3.2.6.3 Priority controlled intersections

(1) T-intersections are preferred instead of cross-junctions or multi-leg treatments.

(2) Roundabouts are only used on roads no more than 1 level apart in the road hierarchy with reasonably balanced traffic flows.

(3) Traffic on major roads approaches should not be unreasonably impeded by minor road approach traffic.

(4) On major roads, roundabouts are only used at the lowest end of the traffic volume range, where single lane operation can suffice. This could be as a staged treatment with single lane approaches before widening to multi-lane standard is required, at which time traffic signals may be installed.

(5) Multi-lane roundabouts (i.e. 2 or more circulating lanes) are not acceptable.

3.2.6.4 Intersection location

(1) Intersections on curves are avoided.

(2) If a T-intersection is located on a curve, the outside of the curve situation is preferred because of better sightlines.

(3) To ensure adequate visibility, intersections are located on a constant grade or in a sag vertical curve.

(4) Intersections near hill crests are avoided.

(5) Major road intersections are not located where longitudinal grades exceed 3%.

3.2.6.5 Intersection spacing

Spacing of intersections on major roads provides for signal coordination between intersections that are planned for signalisation (400–500m), as well as reasonable time intervals between driver decisions for other intersections with lesser roads (150m).

3.2.6.6 Intersection stagger

T-intersections are preferably staggered right–left. This is required to prevent back-to-back turn right lanes and associated sight distance restraints and results in a safer outcome for vehicle operation.

3.3 Minor roads

3.3.1 Design principles

(1) Minor roads are designed to be a priority pedestrian and bicycle environment with low-speed traffic and provide:

(a) property access;

(b) circulation within a local area;

(c) a connection to major roads.

(2) The layout of minor roads should incorporate the following principles:

(a) good pedestrian and cyclist connectivity;

(b) connections to the surrounding public transport, pedestrian and bicycle hierarchies;

(c) circulation between surrounding neighbourhoods promotes travel on minor roads rather than major roads;

(d) no more than 3 minor roads are traversed from any 1 lot to access the nearest accessible district road;

(e) travel time for a vehicle in a low-speed residential environment from an individual lot to connect to a major road is no greater than 90 seconds;

(f) the temporary storage and collection of refuse and recyclables from each lot is considered when planning the layout of the development and subdivision;

(g) turn lanes and special provisions for passing vehicles are not required on minor roads.

(3) For the design of new subdivisions, traffic catchments for minor roads are:

(a) 300 lots for neighbourhood roads;

(b) 100 lots for local roads (excluding laneways).

(4) If an area is accessed by only 1 road that is likely to carry more than 100 vehicles per day, alternative emergency access is provided.

(9) Refer to BSD-2001. 200 Type E kerb and channel is required along a park frontage unless an alternative is approved for water sensitive design.

(10) For water sensitive design, refer to BSD-8301. Alternative kerb and channel types may be acceptable to achieve water sensitive design intent in localised areas.

(11) Where a neighbourhood or local road is identified as either a primary freight route or primary freight access road, the pavement design standards relating to freight identified in section 3.5 will be applicable. Similarly, where a minor road is located within an industrial area or provides access to an industrial use (i.e. low impact industry, medium impact industry, high impact industry, or special industry) the pavement design standards relating to freight identified in section 3.5 will also be applicable.

3.3.4 On-street parking

(1) The availability of on-street parking relates to the width of road pavement, the width of the frontage of the allotments and the size of the traffic catchment to the street.

(2) The standard carriageway cross-section is usually adequate in the provision of parallel parking for visitors.

(3) Additional parking bays are required in the vicinity of cul-de-sac heads where sufficient kerb space is not available.

(4) On local roads with a cul-de-sac head, the limited road frontage, measured from the first approach tangent point, is excluded when assessing on-street parking requirements. Instead, a special parking provision, such as indented bays or central island parking, is provided.

(6) A separation of 0.25m is required between parking bays and the bicycle lane to mitigate effects of door opening.

3.3.5 Lot access

For neighbourhood roads with design traffic volumes of over 3,000 vehicles per day, direct lot access is only provided if the carriageway width provides for separation of parking, bicycle and traffic lanes.

3.3.6 Intersections for minor roads

3.3.6.1 General

(1) Intersections on minor roads are generally priority controlled.

(2) Design of intersections should include a kerb return radius of 6m at street intersections. For freight-dependent development roads, minimum kerb return radius is to be 14m at intersection.

3.3.6.2 Priority-controlled intersections

(1) Priority to the through road is provided at T-intersections while traffic on the terminating road must give way.

(3) Roundabouts in local and neighbourhood roads are designed with a minimum radius of 9m with a 1.5m wide concrete backing strip.

(4) Stop signage is appropriate for four-way cross street intersections on minor roads where traffic volumes in both roads is less than 3,000 vehicles per day.

(5) Traffic lights or other controls are required for minor road to major road connections or where traffic flows exceed 3,000 vehicles per day in any road.

(6) Pavement surface treatment is provided on the 50km/h minor road at the 60km/h major road interface. Threshold treatment may be provided on the minor road at intersections where the minor road is intersecting with a higher sign posted speed. The treatment is to be as per BSD-3166.

3.3.6.3 Intersection spacing

(1) Intersections within the minor road network are located sufficiently far apart to separate the traffic movements at each intersection and to provide a reasonable time interval between driver decisions.

3.3.7.3 Signage

3.3.7.4 Mountable kerbs

(1) The standard mountable kerbs (finished height of 150mm above the adjoining road surface) are generally used in conjunction with speed control devices on minor roads.

(2) Where traffic is intended to regularly mount islands (e.g. apron of speed control devices), the standard mountable kerb should be lowered such that the finished height is 75mm above the adjoining road surface.

3.4 Freight routes

3.4.1 Design principles

(1) Roads that are identified in the freight network are designed for larger design vehicles such as B-doubles and Higher Mass Limit (HML) vehicles. The design and construction of these roads for the freight network must align with the:

(a) structural performance standards for roads that are identified to carry freight vehicles (pavement and structures) and requirements of section 5.3.5;

(b) bridge heights;

(c) lane widths.

(2) This section outlines the standards for the design and construction of all freight routes intended to be owned or maintained by Council including:

(a) primary freight routes;

(b) primary freight access.

3.4.2 Design standards

Table 3.4.2.A lists a summary of the design standards that are applicable for the freight network.

Pavement design requirements for major roads are detailed in section 3.5.

Where a neighbourhood or local road is identified as either a primary freight route or primary freight access road, the pavement design standards relating to freight identified in section 3.5 will be applicable. Similarly, where a minor road is located within an industrial area or provides access to an industrial use (i.e. low impact industry, medium impact industry, high Impact industry, or special industry) the pavement design standards relating to freight identified in section 3.5 will also be applicable.

3.5 Pavement design

3.5.1 Design principles

The underlying principle of pavement design is to achieve a pavement that is functional, structurally sound, has good ride quality, adequate skid resistance, and requires minimal maintenance under the anticipated traffic loading adopted for the design period. The selection process involves adoption of material types, thicknesses and configurations of the pavement layers to meet the design objectives. The design criteria specified in this section are based on the following publications:

3.5.2 Design life

(1) The design life for flexible pavements is 20 years.

(2) When the 20-year design traffic loading (TL20) for flexible pavements exceeds 1 x 107 ESAs, a 40-year design life is required. Council approval may be granted for a shorter design life, where considered appropriate. In these circumstances, the design should include intervention strategies to extend the pavement life to 40 years.

(3) The design life for rigid pavements is 40 years.

3.5.3 Design traffic

(1) The appropriate assessment of the design traffic loading is essential in the production of an acceptable pavement design to cater for the existing traffic and remain serviceable under projected increases in traffic loading throughout the design life of the pavement.

(2) Design traffic shall be calculated in equivalent standard axles (ESAs) for the applicable design life of the pavement.

(3) In addition to published/predicted traffic generation as per the Traffic Impact Assessment Report, actual traffic counts should be used for all roads, so that traffic loading (ESAs) can be calculated and used in the pavement design. The designer should consider present and predicted heavy vehicle traffic volumes, axle loadings and configurations, heavy vehicle growth and street capacity based on the Traffic Impact Assessment Report, or Council information to determine the Design Traffic Loading. The design traffic shall take account of:

(a) the construction traffic associated with the development;

(b) the in-service traffic including any potential industries in the development;

(c) any future developments linked to that development;

(d) the projected loading from external catchments.

(4) The method used to calculate design traffic depends on the type of traffic data available. The selection of the appropriate level of traffic data which are to be obtained should be based on a combination of factors such as:

(a) availability of historical data;

(b) accuracy required;

(c) presence in the traffic spectrum of specialised loadings;

(d) typical axle group or loading distribution.

(5) Where historical data is limited, the designer will need to give consideration to the following design variables:

(a) present traffic volumes;

(b) percentage of heavy vehicles;

(c) road function class;

(d) number of ESAs per heavy vehicle;

(e) growth rate;

(f) design period.

(6) In industrial areas, where specific future uses are known. (e.g. a freight-dependent development such as a particular large manufacturing plant or distribution centre), appropriate generation rates for that future use or uses should be used. However, in cases where the future industrial uses will not be known, and given the potentially wide variation in traffic generation, depending on location, industry type, number of employees, amount of retailing etc. generation rates assumed for pavement design must necessarily be conservative.

(7) For preparing traffic studies, evidence indicates that heavy vehicles avoid peak periods where possible, therefore 6-hour peak period counts may not give an accurate indication of pavement loading caused by heavy vehicles. For upgrading and widening of existing roads and/or extensions of the existing network, 7-day classified counts are to be used where vehicles are separated into Austroads vehicle classifications. Twelve-hour traffic counts may be used to interpret historical trends and growth rates.

(8) The pavement design report shall include all traffic data and/or assumptions made in the calculation of the design traffic.

(9) Where reliable traffic data is not available, presumptive traffic loading is allowed for local and neighbourhood roads without bus services as detailed in Table 3.5.3.A.

3.5.3.1 Traffic counts

Manual and automated intersection counts have been regularly performed throughout Brisbane. The older counts provide a historical record and may be used to predict trends in growth rates.

3.5.3.1.1 12-hour intersection counts

(1) Typically, the 12-hour counts represent approximately 80% of the daily traffic. The 12-hour count is multiplied by 1.25 to calculate daily traffic.

(2) Twelve-hour intersection counts provide the number of heavy vehicles without the Austroads classifications. The ESA per heavy vehicle can be ascertained using Table 3.5.3.1.1.A.

(3) The annual traffic can be estimated by multiplying the weekday traffic by the number of days/year taken as 310 days/year. However, on some roads, such as those adjoining major retail centres and sporting venues, a factor of 365 is appropriate.

Table 3.5.3.1.1.A—ESA/HV equivalencies according to road classification (not used for automated classified counts)

(2) This data is based on the typical traffic spectrum containing a mixture of loaded and unloaded vehicles. Where the traffic spectrum is not typical e.g. haul routes with all loaded vehicles in the same direction and bus routes, higher ESA/HV equivalencies should be derived and used. If site-specific design traffic standards for ESA/HV are available, these should be used in place of the representative data shown in Table 3.5.3.1.2.A.

3.5.3.2 Traffic loading calculation

(1) Selecting the appropriate traffic loading is essential for achieving the desired service life. There are 2 main classes considered for pavement design:

Note—(1) The annual traffic can be estimated by multiplying the weekday count by the number of days/year. The minimum value is 310 days/year. However, on some roads, such as those adjoining major retail centres and sporting venues, a factor of 365 is appropriate.

(4) Part of the task of estimating the cumulative traffic loading (in the design lane) over the design period is to estimate the likely changes in daily traffic loading during this period. The compound growth of traffic is usually defined as a percentage increase in annual traffic volume – a typical statement being ‘the annual growth rate is R%’. The cumulative growth factor over the design period is calculated as follows (Austroads 2010):

for R>0

(2)

for R=0

where:

CGF

=

cumulative growth factor (-)

R

=

annual growth rate (%)

P

=

design period (years)

(5) A range of annual growth rates are presented in Table 3.5.3.2.B for design periods of 20, 25 and 40 years. For other design periods, Equation (2) can be used to calculate the cumulative growth factor (CGF).

Table 3.5.3.2.B—Cumulative growth factor (CGF) values

Design period (P) (years)

Annual growth rate (R) (%)

0

1

2

3

4

6

8

10

20

20

22

24.3

26.9

29.8

36.8

45.8

57.3

25

25

28.2

32

36.5

41.6

54.9

73.1

98.3

40

40

48.9

60.4

75.4

95

154.8

259.1

442.6

(6) The cumulative growth factor (CGF) values in Table 3.5.3.2.B assume that the traffic volumes are below the saturation capacity for the entire design period. The designer should check whether the saturation capacity is likely to be exceeded during the design period and whether any upgrading of road capacity is planned.

Increased pavement damage occurs when vehicles are turning at intersections and roundabouts. Uneven load distribution causes higher loads on one wheel path compared to the other and load transfer induces horizontal shear forces which can increase pavement damage significantly. Additional stresses are also generated on long, steep grades (greater than 10%) and at intersections (e.g. due to braking). At these locations, the load-induced damage may be compounded by the slowly moving load, which has a detrimental effect on the visco-elastic performance of asphalts. To allow for these effects, the traffic loading (ESA) must be increased by a factor of 1.3 in these locations. The designer need not adjust the asphalt modulus in the Mechanistic Design Procedure for low-speed environments, since this effect is considered by the increased damage effect (IDE) factor.

Table 3.5.3.3.A—Increased damage effect (IDE) values

Location

IDE value

On grades >10%, intersections, roundabouts and bus stops

1.3

Any other road section

1.0

3.5.3.4 Higher mass limit (HML) vehicles and B-double routes

(1) Higher mass limits (HML) allow for increased mass limits (axle loads) on approved routes for specific vehicles fitted with road-friendly suspension systems and operated in accordance with the Intelligent Access Program (IAP). Due to the low operating speeds of much of the Council road network, when assessing the implications of HML vehicles in pavement designs, no road wear reduction factors are to be applied to the design loads when using road-friendly suspensions.

(2) The Department of Transport and Main Roads (DTMR) is the regulating authority for higher mass limit (HML) and multi-combination (B-doubles) vehicles in Queensland and maintains the maps of approved routes for these classes of vehicles. Where a pavement forms part of an approved or proposed route, the calculated design traffic shall be multiplied by a factor of 2 to allow for the effects on the pavement caused by rapid loading of subsequent axle groups and reduced slow speed of travel. On roads within 200m of approved B-double and/or HML routes (except local residential access streets), on designated or proposed freight routes, in all industrial areas and freight-dependent development, this factor must be applied.

Table 3.5.3.4.A—Higher mass limit (HML) values

Roads within 200m of designated HML and B-double routes other than local roads

Designated or proposed freight routes

All freight-dependent development access roads

2

Any other road section

1

(3) Where a freight-dependent development is proposed to have access available to HML and/or B-double vehicles, the route from the development to an existing 'approved' HML and/or B-double route shall be assessed and, where there is inadequate pavement strength, be upgraded to the standard suitable for HML and/or B-double vehicles.

3.5.3.5 Design traffic at intersections

Design traffic at an intersection must be calculated by adding the design traffic applicable to one road to the design traffic applicable to the crossroad. Selection of the pavement structure should be based on minimum maintenance requirements.

3.5.3.6 Deemed to comply design traffic loading for small areas

For road widening and extensions to roads subject to heavy traffic loading, the design traffic loading should be based on the results of the traffic study using actual traffic counts. However, for small areas of pavement construction (typically less than 200m2), the nominal/minimum traffic loadings for the various road classifications given in Table 3.5.3.6.A can be used. Allowances for increased damage effect (IDE) and HML values are incorporated in the nominal design traffic in Table 3.5.3.6.A.

Table 3.5.3.6.A—Design traffic by road type for flexible pavements

Road classification

Design Life

Nominal design traffic (ESA)

District

20 years

Minimum 6.0 x 106

Suburban

20 years

Minimum 6.0 x 106

Freight-dependent development

20 years

Minimum 1.0 x 107

Arterial

40 years

Minimum 3.8 x 107

3.5.4 Subgrade evaluation

3.5.4.1 General

(1) The design parameter for the subgrade is the California Bearing Ratio (CBR). The pavement design must be based on the soaked CBR tests being representative of the subgrade over the various lengths of road at the box depth.

(2) A design CBR must be determined for each unique section of road defined on the basis of topographic, geological and drainage conditions at the site. In determining the design CBR, account should also be taken of the variation of the subgrade strength with depth below subgrade level. The critical layer of material should be established to ensure each layer has adequate cover.

3.5.4.2 Sampling frequency

(1) Subgrade must be evaluated at the following frequencies:

(a) road length ≤ 120m: not less than 2 tests for each subgrade type.

(b) road length > 120m: 1 test for every 60m or part thereof, but not less than 3 tests for each subgrade type.

(2) Spacing of test sites must be selected to suit subgrade, topographic and drainage characteristics.

3.5.4.3 Laboratory determination of design Californian Bearing Ratio

(1) The design CBR must be based on the soaked condition in the subgrade at a compaction of 100% standard, that is, the design CBR is the four-day soaked CBR as determined by testing in accordance with AS 1289.6.1.1 (single point test).

(2) When the subgrade CBR is particularly sensitive to changes in moisture content, adequate testing of the CBR over a range of moisture contents and densities must be provided and CBR interpolated at the design moisture content and density conditions, that is, 4-point test using DTMR Test Method Q113A.

3.5.4.4 Maximum design CBR

A maximum subgrade CBR of 10 is to be used for design purposes. Granular subgrade with CBR values greater than 10 and which have a known in-situ service life may be accepted if accompanied by a certified geotechnical report.

3.5.4.5 Soft subgrades

(1) If the CBR determined for the subgrade is less than CBR 3 for flexible (granular, full depth asphalt or stabilised) pavement and CBR 5 for concrete pavement, then one of the following subgrade treatment options is required:

(b) carry out lime stabilisation treatment in accordance with the methodologies set out in section 3.5.6.4;

(c) use other techniques such as rock spalls on geotextile, geogrids together with correctly sized gravel blanket course etc.

Table 3.5.4.5.A—Minimum depth of subgrade replacement

In-situ subgrade design CBR

Minimum depth of subgrade replacement (mm)

2.5%

150

2.0%

200

1.5%

300

1.0%

400

<1.0%

Specific assessment required

(2) The proposal for subgrade treatment needs to be submitted to Council for approval. After subgrade improvement, the pavement design should be based on subgrade CBR 3 for flexible pavement and CBR 5 for concrete pavement.

3.5.5 Design procedure

There is a distinction between the design principles that are applied to roads subject to light-traffic and heavy-traffic loadings. Light-traffic loading is considered to be a 20-year design traffic loading of up to and including 1 x 106 ESA with heavy traffic loading being greater than 1 x 106 ESA.

3.5.5.1 Roads subject to light traffic loadings – TL20 ≤ 1 x 106 ESAs

Roads subject to light traffic loadings have design traffic up to TL20 of 1 x 106 ESA. It is expected that cul-de-sacs, local roads and neighbourhood roads without bus services fall within this classification.

3.5.5.1.1 Granular pavement

(1) Granular pavements with thin asphalt surfaces are likely to be suitable for these roads. Above TL20 of 1 x 106 ESA, for granular pavements with relatively thin asphalt surfacing, the fatigue life of the asphalt is likely to be significantly less than the design life of the granular pavement. In such cases, the asphalt has to be regularly replaced, rejuvenated and/or overlaid, which is unacceptable to Council.

(2) The granular pavement comprises the majority of Council’s lightly trafficked road network. Council prefers this pavement type as it provides the lowest whole-of-life costs, enables ready access for installing and maintaining utilities, the best opportunities for rehabilitation in urban residential situations and acceptable ride quality. This pavement is also the most cost-effective pavement to construct.

(3) All granular pavements must be sealed with a prime coat or a primer seal prior to surfacing with asphalt.

(6) Notwithstanding that Figure 3.5.5.1.1a may indicate a lesser pavement depth, the minimum pavement and individual course thicknesses for roads subject to light traffic loading are given in Figure 3.5.5.1.1a.

(7) Continue pavement at least 75mm past the back of the concrete kerb and channel (CKC) to ensure stability of the pavement edge. Provide minimum 75mm crushed rock bedding under the concrete kerb and channel as shown on BSD-2041.

3.5.5.1.2 Full depth asphalt pavement

(1) This pavement is not generally used for local roads. However, it is may be used in areas where the speed of construction is critical or for narrow pavement widening. The full depth asphalt pavement shall be designed in accordance with section 3.5.5.2.2.

(2) Where full-depth asphalt pavements are to be constructed alongside existing granular pavements, the design must consider the possible effect on subsoil drainage of the pavement, and the need for additional subsoil drainage to prevent ‘tanking’.

3.5.5.1.3 Concrete pavement

(1) Full-depth concrete roads are generally used only for roads subject to heavy traffic loading (i.e. all roads with 20 year design traffic > 1.0 x 106 ESA). However, a full-depth concrete road can be designed for roads subject to light traffic loadings, subject to the following requirements:

(1) Roads subject to heavy traffic loading are all roads with estimated traffic TL20 of greater than 1.0 x 106 ESAs over a 20-year period. They also include freight-dependent development roads as a subset. The design traffic loadings are adjusted to account for the effects on the pavement of the introduction of new generation heavy vehicles (HV) (including buses) and Higher Mass Limits (HML).

(2) It is expected that neighbourhood roads with bus services, district, suburban, freight-dependent development, and arterial roads will fall within this category.

3.5.5.2.1 Granular pavement

Granular pavements with thin asphalt surfacing are NOT acceptable for roads with TL20 greater than 1.0 x 106 ESAs.

3.5.5.2.2 Full-depth asphalt

(1) Designs for full-depth asphalt pavements may be based on Figure 3.5.5.2.2a for asphalt containing Class M1000 multigrade bitumen. The thickness of the asphalt layers in this figure includes the allowance for the construction and design tolerances.

(2) Full-depth asphalt shall be placed on a minimum of 150mm thick granular working platform except for roads where TL20 > 1.0 x 107 ESAs over a 20-year period where a minimum of 300-mm thick granular working platform is required. However, the actual thickness required is a function of the subgrade strength and working platform over 300mm thick may be required for low strength subgrade. The granular working platform should comprise the following layers in accordance with Reference Specifications for Civil Engineering Work S300 Quarry Products:

(3) The granular working platform shall not be considered as a structural layer.

(4) Notwithstanding that Figure 3.5.5.2.2a or the mechanistic pavement design method may indicate a lesser pavement depth, the minimum pavement and individual course thicknesses for roads subject to heavy traffic loading are given in Table 3.5.5.2.2.A.

(5) Where full-depth asphalt pavements are to be constructed alongside existing granular pavements, the design must consider the possible effect on subsoil drainage of the pavement, and the need for additional subsoil drainage to prevent ‘tanking’.

Note—Modulus is also a function of the way it is measured (i.e. the specific laboratory procedure used to measure the stiffness of a sample of material). Hence, caution should be used when quoting a modulus value from a reference source. A detailed discussion is outside the scope of this guideline.

(2) The difficulties with this approach is its complexity and the lack of available data on the actual traffic spectra. Presumptive traffic load distribution (TLD) values in Table 3.5.5.2.2.1.A may be used to simplify the design process by converting SAR back to ESA.

(3) The subgrade performance is based on the Austroads (2012) compressive strain relationship.

3.5.5.2.2.3 Damage functions for conventional asphalt fatigue:

The fatigue performance for asphalt containing conventional bitumen is based on the Shell relationship:

where:

N

=

allowable number of repetitions of the load for asphalt produced using conventional bitumen

=

tensile strain produced by the load (microstrain)

Vb

=

percentage by volume of bitumen in the asphalt (%)

Smix

=

Asphalt modulus (MPa)

RF

=

reliability factor for asphalt fatigue

(on Council projects RF = 1)

3.5.5.2.2.4 Damage functions for multigrade asphalt fatigue:

The fatigue performance for asphalt containing multigrade bitumen is based on Council research:

Where:

NMultigrade

=

allowable number of repetitions of the load for asphalt produced using multigrade bitumen

=

tensile strain produced by the load (microstrain)

RF

=

reliability factor for asphalt fatigue (on Council projects RF = 1)

Note—Asphalt modulus = 3468MPa

3.5.5.2.2.5 Construction and design tolerances in pavement design

(1) Construction and design tolerances are taken into account in the pavement design process by increasing the thickness of the critical structural asphalt layer and the critical unbound layer:

(a) for rehabilitation projects which are likely to be constructed under traffic with limited survey control, increase the thickness of the structural asphalt layer by 20mm;

(b) for new construction with good survey control, increase the thickness of the structural asphalt layer by 10mm and the thickness of the upper most unbound layer by 20mm.

(2) The added tolerances reflect the uncertainty and variability of the materials and technology. If the CIRCLY design, plus the added tolerance, is less than the minimum layer thickness specified by Council, then the minimum requirement must be adopted. The layer thickness limits for individual asphalt layers are outlined in Reference Specifications for Civil Engineering Work S320 Laying of Asphalt.

3.5.5.2.3 Concrete pavement

Full-depth concrete roads must be designed in accordance with the Guide to Pavement Technology – Part 2: Pavement Structural Design (Austroads 2012) considering the 2 distress types: fatigue of the base and erosion of the sub-base/subgrade. The concrete shall have a 28-day compressive strength of not less than 40MPa. A bond breaker such as bituminous seal, wax or other approved material must be included between the lean mix sub-base and concrete base. The proposed design must be submitted to Council for approval.

3.5.6 Treated pavements

3.5.6.1 General

(1) ‘Upside down’ pavements (i.e. pavements which have an unstabilised upper granular base layer placed over a stabilised granular sub-base layer) will not be approved. The stabilised granular layer must extend to the underside of the asphalt layer.

(3) The proposed design, together with the results of tests undertaken to determine the design and to prove the adequacy of the material to satisfy design requirements, must be submitted to Council at least 2 weeks prior to commencement of the work. A NATA-registered laboratory shall undertake all the required testing.

3.5.6.2 Cementitious blend treated materials

(1) Council will permit cementitious blend stabilisation of granular pavement with thin asphalt surfacing on lightly trafficked roads, where the 20 year design traffic loading is below 1.5 x 106 ESA. Cemented materials will inevitably crack due to thermal and shrinkage stresses, resulting in reflective cracking of the asphalt surface. While this may be tolerable on lightly trafficked roads, it is not acceptable on heavily trafficked roads and the Guide to Pavement Technology – Part 2: Pavement Structural Design (Austroads, 2012) indicates that 175mm of asphalt is required to inhibit this reflective cracking. This renders such pavements uneconomic. However, cracking due to thermal and shrinkage stresses can be limited by good design and construction methods.

Note—Although not mandatory, the maximum cement content should be limited to 4.5% by weight to limit reflective cracking of shrinkage cracks in the treated layer and asphalt surfacing.

(2) After construction, the cement treated pavement must be immediately sealed with a primer seal for a minimum 4-week curing period prior to surfacing with asphalt. The pavement must be tested using a falling weight deflectometer (FWD) after the minimum curing period and prior to placing of the asphalt. Test results must be submitted to Council for approval.

3.5.6.3 Bitumen stabilisation

Any proposal for foamed bitumen or bitumen emulsion stabilisation of granular pavement material will require the design to be prepared by experienced personnel according to Queensland Department of Transport and Main Roads specifications. The proposed design must be submitted to Council for approval.

3.5.6.4 Lime stabilisation

(1) Lime stabilisation of the base or sub-base is generally not acceptable as a pavement treatment. Lime stabilisation of the subgrade may be acceptable.

(2) Testing will need to be carried out in accordance with Pavement Recycling and Stabilisation Guide (2015). Specifically, lime demand tests and UCS testing of prepared samples must be carried out to determine the amount of lime required and the strength gains achieved.

3.5.7 Subsoil drainage

Refer to Standard Drawing BSD-2041 for details. Sub-surface drains should be used to protect the road structure from moisture ingress. Typical cross-section pavement details should show side drains. Unless otherwise approved by Council, side drains should be provided at the following locations:

(a) both sides of all streets and roads under the kerb and channel, except where Council determines that such drains are unnecessary or disadvantageous;

(b) under the kerb around all landscaping areas, depending on location. Landscaping in footpaths should not be placed immediately behind the kerb. Landscaping adjacent to pavements must not have irrigation systems;

(c) across the end of the road at the stage boundary. This must be removed when the next stage is built;

(d) along the line of fill when subsoil water is affected by the compaction of the fill;

(e) where springs are located;

(f) where moisture can ingress;

(g) under the invert of flat grassed overland flow paths in areas that are usually subject to pedestrian or vehicle traffic;

(h) at the toe of cuttings greater than 2m high;

(i) blanket courses should be limited to areas with grades <5% and should not be used where they may affect the structural integrity of the pavement.

3.5.7.1 Other special purpose drainage systems

(1) Other locations/situations that should be considered for sub-surface drainage include:

(b) soft areas, whether excavated and backfilled or not, provided a drainage outlet can be obtained;

(c) large pipe trenches, underground water courses, service conduits, water supply pipes and existing or abandoned utility trenches backfilled with permeable material;

(d) along the high side of a pavement where seepage is evident, or where water may enter from batters, full-width pavement, service trenches, permeable medians or abutting properties;

(e) along both sides of the pavement where the cross-slope is flatter than 2% (e.g. in transitions to superelevation).

(2) There is no exact method of preventing the harmful effects of water. Often the problems could require several of the typical drain types being combined with the use of mitre drains for a satisfactory solution.

3.5.7.2 Widening of existing pavements

(1) A common problem associated with the widening of an old gravel pavement is the accumulation of moisture at the join between the new and old pavement resulting from the use of materials of different permeability (and boxed-out construction).

(2) For patches and new pavement construction where the new pavement material is likely to trap water within the adjacent existing materials, sub-surface drainage should be installed on the high side of the new pavement. If the bottom of the new pavement is located within the subgrade such that it creates a sump, sub-surface drainage should also be installed on the low side of the pavement. If the drain pipe or prefabricated geo-composite strip drain is located within a fine silt or clay subgrade, then filter sand should be placed around the drain prior to backfilling with no-fines concrete (NFC) to prevent fine silty particles from entering and blocking the drains. For significant works, drainage design should be undertaken.

3.5.8 Road surfacing

3.5.8.1 Performance requirements

(1) Selection of the pavement surfacing must be based on the performance criteria, the 2 most important being deformation resistance and skid resistance. Rutting and shoving problems should be catered for by the selection of appropriate material types and properties. Consistent with achieving these requirements, the surfacing should provide minimum maintenance requirements.

(3) Edge restraints must be provided along the perimeter of all paved areas. They should be able to support traffic loads and to prevent the escape of the pavement material, where required, from beneath the paved surface. An edge restraint may be in the form of a kerb, combined kerb and channel, established structure or rigid flush abutment.

3.5.8.2 Asphalt

(1) Asphalt is the preferred surfacing material for all roads within the road hierarchy. For coloured treatments on asphalt surfaces, refer to section 3.5.8.4 for specific requirements. The following asphalt types may be used in Brisbane:

(a) dense-graded asphalt (DG);

(b) stone mastic asphalt (SMA) may be used subject to Council approval;

(c) proprietary products such as micro-surfacing, SAMI Fricseal etc. need to be submitted for approval.

(2) The following asphalt types will generally not be approved for use:

3.5.8.3 Concrete

(1) A wide variety of surface finishes are available for concrete pavements. There is no restriction on the use of tyned- or broomed-surface finish. The concrete shall have a 28-day compressive strength of not less than 40MPa. For coloured treatments on concrete surfaces, refer to section 3.5.8.4 and Reference Specifications for S155 Road Pavement Markings for specific requirements.

(2) Exposed aggregate surface is permitted in local traffic area threshold treatments provided that the crushed aggregate finish:

(3) Stamped concrete is not permitted as the surface texture can cause a potential hazard for cyclists.

3.5.8.4 Coloured surface treatments

Coloured surface treatment must serve a traffic management function such as thresholds at local traffic areas and to visually enhance school zones. The use of coloured surface treatment as an aesthetic enhancement to the streetscape is not permitted.

3.5.8.5 Segmental pavers

3.5.8.5.1 General

Segmental pavers may be used, although future maintenance considerations should be taken into account when approval is sought for their use on road pavements. Pavers must be laid to the herringbone or stretcher bond pattern and are only permitted on roads subject to light traffic loadings (TL20 ≤ 1.0 x 106 ESA).

3.5.8.5.2 Limitation of use

Pavers should be restricted for use in local traffic area threshold treatments, landscaping features in speed control devices, traffic medians and traffic islands. As a guide, the areas of pavers should not make up more than 10% of the total road pavement area. Types of paver, colour, manufacturer, product number etc. should be shown on the engineering drawings. Slip and skid resistance values and permitted colours should comply with Reference Specifications for Civil Engineering Work – S150 Roadworks.

3.5.8.5.3 Treatment around obstructions

The preferred method for treatment of pavers around gullies, maintenance holes, service pits and similar obstacles is to use specifically manufactured pavers, designed to be placed around these obstructions. Pavers adjacent to these obstructions or the lip of the kerb and channel should have the arris reduced to a 5mm radius to narrow the gap between the pavers and the adjacent structures.

3.5.8.5.4 Pavement design

The pavers should not be considered as contributing to the structural strength of the pavement. The detail of the pavement design should be shown on the engineering drawings. A typical entrance threshold treatment is shown on Standard Drawing BSD-2041. The acceptable standard of pavement composition for residential streets should comprise a minimum 60-mm thick pavers laid on 25-mm thick cement mortar bed, and founded on a reinforced concrete base not less than 210mm thick.

3.5.8.5.5 Drainage

Particular attention needs to be paid to the design and construction of road drainage for paved roads, in particular sub-surface drainage. Refer to Standard Drawing BSD-2041. No-fines concrete blocks or PVC tubes placed over side drains to drain the pavement are not an acceptable design. Full details of the sub-surface drainage should be shown on the engineering drawings.

3.5.8.5.6 Edge treatment

Edge restraints should be provided along the perimeter of all paved areas. The minimum standard for edge restraint is 230mm x 230mm with one Y12 reinforcing bar (refer Standard Drawing BSD-2001). An isolation joint is required at the junction of the channel. A header course (full size pavers laid side by side) should be used along the edge of the road pavement abutting a kerb or channel or any footpath or median edge or edge restraint.

3.5.8.5.7 Transverse restraints

Cross beams and/or restraints are required for inclined areas and roadways, and also for surfaces where heavy vehicular braking may cause shoving of pavers. Details should be included in the engineering drawings.

3.6 Bicycle routes

3.6.1 Design principles

(1) The bicycle network provides safe, convenient and continuous cycle routes that encourage cyclists of all ages and abilities to ride for transport and recreation.

(2) The on-road bicycle routes of the bicycle network provide:

(a) bicycle lanes;

(b) priority intersections and road crossings;

(c) regulatory and way-finding signage;

(d) bicycle facilities such as bicycle parking.

(3) The on-road bicycle routes of the bicycle network intended to be owned or maintained by Council include:

(a) primary bicycle routes;

(b) secondary bicycle routes;

(c) local bicycle routes.

(4) The design standards for off-road bicycle routes are stated in Chapter 4 of this planning scheme policy.

(5) The design standards for Riverwalk are stated in Chapter 12 of this planning scheme policy.

3.6.2 Design standards and standards for bicycle routes on roads

(1) A summary of the design standards that are applicable to the bicycle network that is located in the road reserve, are as follows.

(a) some parts of the bicycle network might not comply with all the current specified standards;

(b) bicycle lanes are provided on all major roads.

(2) Guidance on provision for cyclists on the carriageway is provided in BSD-5102.

3.6.3 Cross-section

3.6.3.1 General

(1) This section outlines additional design standards for bicycle works on roads in addition to those outlined in section 3.6.2.

(2) The cross-section elements include:

(a) bicycle lanes;

(b) verges;

(c) on-street parking;

(d) intersections.

3.6.3.2 Bicycle lanes

(1) The width of a bicycle lane is dependent on the speed of the traffic and is shown in Table 3.6.3.2.A. The width of a bicycle lane is measured from the nominal face of kerb. The minimum width of a bicycle lane is 1.5m.

(2) Bicycle lanes are constructed with full depth pavement and a smooth surface flush with the vehicular lanes and gutters.

(3) Wide kerb lanes of 4.5m are required to accommodate a bicycle lane where off-peak kerbside parking is permitted, or as part of a parking lane.

(4) A minimum sealed carriageway width of 5.5m is required on all one lane major roads identified as part of the bicycle network.

(5) The minimum sealed carriageway width cannot be relaxed if the lane is adjacent to a median.

(6) It is recommended that car parking is prohibited adjacent to bicycle lanes by using yellow edge line and/or regulatory signage.

(7) Neighbourhood roads identified as primary or secondary routes in the bicycle network, and carrying over 3,000 vehicles per day provide:

(a) bicycle lanes; or

(b) 4.5m wide kerbside lanes, where kerbside parking is required.

(8) Where an on-road bicycle route is also a freight route, bicycle lanes must be 2m wide.

Table 3.6.3.2.A—Width of bicycle lane

Sign-posted speed

Bicycle lane width

60km/h

1.8m

80km/h

2.0m

3.6.3.3 Verges

(1) Where the bicycle network proposes to provide off-road paths on the verge, the verge width should be increased accordingly.

(2) Verge widths to be increased to a minimum 6m where an off-road path greater than or equal to 3m is identified by the bicycle network.

(3) On-verge bicycle paths of 3m to 3.5m width in addition to the on-road bicycle lanes and crossings are typically provided in the vicinity of schools for use by children, where it is preferred that they not ride on the carriageway.

(4) Bicycle, shared or separated paths along roads that front Council managed natural assets and parkland should be aligned to protect significant vegetation in accordance with the Natural Assets Local Law.

3.6.3.4 On-street parking

(1) Wide kerb lanes of 4.5m are required where off peak kerbside parking is permitted on roads that are identified by the bicycle network.

(2) Where a bicycle lane is provided adjacent to a parking lane, the potential conflicts and safety issues for cyclists need to be resolved.

(3) In some instances, parking may not be appropriate adjacent to a primary route.

3.6.3.5 Intersections

(1) Bicycle lanes are required on the approach and departure of all legs of signalised intersections on all major roads, as well as minor roads identified as bicycle routes in the bicycle network.

(2) Signalised bike crossings are provided where an off-road pathway on the verge crosses a road or in locations where separation of high volumes of pedestrians and cyclists is required at a signalised intersection.

3.7.3 General design standards

This section provides a summary of the general design standards for streetscapes.

3.7.3.1 Verge layout

(1) The verge layout must be designed in accordance with the relevant streetscape hierarchy designation.

(2) The typical verge layouts allow for planting and elements to be laid out to suit the kerbside allocation, adjacent building layout and verge constraints.

3.7.3.2 Minimum verge width

(1) The minimum standard width for verges when constructing a new road is 4.25m.

(2) The minimum standard verge width for existing established areas is 3.75m.

(3) The standard verge widths may be varied by the public transport, bicycle or streetscape hierarchies.

(4) The standard verge width is maintained where indented bus bays are located.

(5) The minimum standard width of a verge may be relaxed to no less than 2.5m in the following circumstances:

(a) where the existing verge width is consistently narrower than the standard width for the length of the street block, or to accommodate constrained pinch points for a short distance only;

(b) where the streetscape type is not a subtropical boulevard in a centre (SB1), city street (CS1 or CS2) or neighbourhood street major (NS1).

(6) In such exceptional circumstances it must be demonstrated that pedestrian facilities and service utilities can be accommodated within the reduced width. Each case will be assessed on its merits.

3.7.3.3 Verges – bikeway

(1) Where the bicycle network is proposed to provide paths on the verge, the verge width should be increased accordingly.

(2) The standard verge width is to be increased where on-verge bicycle and pedestrian separated or shared path is greater than or equal to 3m as identified by the bicycle network.

(3) If on-verge bikeways of 3m to 3.5m width in addition to the on-road bicycle lanes are provided, crossings are typically provided in the vicinity of schools for use by children.

3.7.3.4 Existing significant vegetation

Verge design avoids the clearing or disturbance of significant vegetation in the verge where identified by the Natural Assets Local Law and where roads front existing or proposed Council-managed natural areas and parkland. In these situations, walkways, bikeways and drainage features should be aligned to protect significant vegetation.

3.7.3.5 Verge crossfall

(1) Council will not allow the resolution of levels for access to buildings or flood mitigation in the verge.

(2) The verge is to be free of steps, ramps and trip hazards.

(3) A crossfall of 1V:50H is to be provided on the verge.

(4) If constraints limit the formation of the verge to the correct profile across the full width, a section of verge with a minimum width of 2.5m at the ultimate level with maximum 1V:40H crossfall may be appropriate.

(5) The crossfall of the verge may be varied where significant trees are to be retained.

(6) A 0.3m offset is required from the property boundary to the commencement of a batter on private land that adjoins a road reserve where the batter is steeper than 1V:6H.

(7) All cut and fill batters are located outside the road reserve or access restriction strip.

3.7.3.6 Verge longitudinal grade

(1) Verge design achieves a uniform longitudinal gradient along the full length of the verge and ties in with the existing line and level of adjacent verges and kerb.

(2) The maximum longitudinal grade on any verge corresponds to the maximum grade of the road.

3.7.3.7 Scope of paving works

All verge works provide new pavement finishes, new or reinstated kerb and channel, driveways, pedestrian kerb crossings, tactile paving, roof-water drainage line connections and service pit lids.

3.7.3.8 Corners—intersection of verges

Where 2 streets with different streetscape hierarchy classifications meet, the higher order street type will take precedence and its layout will wrap around the corner into the minor order street. The extent and detail of the treatment wrapping around the corner will vary.

3.7.3.9 Tactile ground surface indicators (TGSI)

(1) Tactile ground surface indicators (TGSIs) are installed to provide guidance and/or warning of an obstruction or hazard in any location where insufficient alternative or ‘natural’ tactile cues exist.

(2) TGSIs must not be proliferated unnecessarily.

(3) TGSIs must be used where the obstruction, hazard or change of direction of travel is less likely to be expected or anticipated and could be encountered, perhaps injuriously, in the absence of a suitably placed TGSI.

3.7.3.13 Water sensitive urban design measures

(1) Kerb inlets are to comply with the requirements of the Healthy Water’s water sensitive urban design policy.

(2) Rain gardens may be appropriate in verges with low pedestrian traffic volumes where it can be demonstrated that the rain garden will not impact on pedestrian movement, kerbside allocation, access to public transport, services location or access, or provision of street trees.

(3) Applications for proposed rain gardens will be assessed case by case.

3.7.3.14 Entrance features to new subdivisions

Sales marketing features such as walls, waterfalls, fountains, flagpoles, ornate entrance structures, non-standard landscaping and the like must not protrude onto the verge (road reserve) or any access restriction strip.

3.7.3.15 Landscaping to speed control devices

(2) The general treatment of traffic islands should comprise a mixture of landscaping and hard surface infill.

(3) The selection of plants must take into account the following traffic design criteria:

(a) sightlines and distances at intersections and speed control devices;

(b) tree form, shape and location within the road reserve must not encroach into the space required for a vehicle to pass through a speed control device.

(4) Plant species should be selected on hardiness, suitability of soil type, micro-environment and landscape character, and are to be selected from the general species tables for the relevant street type.

3.7.3.16 Landscaping to medians

(2) For medians less than 1.5m in width, landscaping or turf is not provided. In these areas a concrete infill, usually stencilled or exposed aggregate concrete or concrete pavers, is necessary.

(3) Where surfaces are steeper than 1V:4H, hard surface treatment is provided.

(4) Medians and islands that are planted rather than concrete infilled are designed to accommodate landscape works by providing:

(a) a median kerb keyed 135mm into the pavement;

(b) a 300mm concrete backing strip behind the kerb;

(c) adequate site preparation and soil depths;

(d) root barriers where needed;

(e) conduit for future tap connection;

(f) subsoil drainage discharging to an enclosed pipe system.

3.7.3.17 Structures

Non-standard elements and structures such as planters, walls, shade structures and decks are not permitted in the verge.

3.7.3.18 Roof drainage connections

(1) Outlet for roof water drains on the high side of one-way crossfall paved streets are not permitted in the kerb. Roof water reticulation is required in this situation with the outlet into the main underground drainage stormwater system.

3.7.4.4 Neighbourhood streets

3.7.4.4.1 Typical layout

(2) Note that for neighbourhood streets minor (NS2), a concrete footpath is only constructed in instances where pedestrian traffic volumes require it. Such instances will be determined on a site-by-site basis.

Table 3.7.4.4.1.A—Neighbourhood streets

Design requirement

Neighbourhood street major—NS1

Neighbourhood street minor—NS2

Verge width

3.75m (4.25m new roads)

Description

Concrete footpath in turf

Unobstructed pavement width

1.8m

1.2 m(1)

Street trees

Street trees:

(a) all trees minimum of 750mm from nominal face of kerb and 600mm from edges of pavement;

(b) mix of tree species laid out in an informal manner with clusters of trees;

(c) medium- and small-crown trees to be planted at minimum 2m spacing, if within garden beds, or minimum 6m spacing outside of garden beds;

(d) large-crown feature trees to be planted at minimum 10m centres.

Turf strip adjacent kerb – minimum width

1.3m minimum

1.3m minimum

Turf strip at rear of verge

0.5m

(1m for new roads) (2)

1.1m

(1.6m for new roads) (2)

Tree planting beds – minimum widths

1.2m

Furniture

No furniture

Notes—

(1) Where required.

(2) Where concrete footpath is required.

3.7.4.4.2 Standard palette

The standard palette in Table 3.7.4.4.2.A is to be applied in the design and construction of all neighbourhood streets.

3.7.5 Design standards for street tree planting

3.7.5.1 Set out from kerb

(1) Street trees are planted 750mm from nominal face of kerb for verges up to 4.25m wide, and 950mm from nominal face of kerb for verges greater than 4.25m wide in accordance with BSD-1013, BSD-1014, BSD-1015 and BSD-1016.

(2) Street tree setback from kerb is greater for industrial streets, to accommodate the prevalence of larger vehicles along the kerbside.

(3) The location must accommodate the ultimate size and shape of the tree.

3.7.5.2 Existing and replacement street trees

(1) Existing street trees are to be retained and protected unless removal is negotiated and approved by Council.

(5) Where planted in corner land dedications, large-crown feature trees have a minimum setback from kerb of 3.75m, and minimum branch height clearance of 4.5m within 1.5m of the kerb, to ensure sightlines at intersections are maintained for motorists.

3.7.5.7 Tree trenches

3.7.5.8 Tree planting surrounds

The streetscape type determines whether trees are to be planted in mulch, garden beds, tree grates, or permeable and porous paving.

3.7.5.9 Species

Where not identified in Chapter 5 of this planning scheme policy, plantings within entire streets may include a mix of species allowing for some consistency of individual feature trees at focal points such as roundabouts, ends of local access streets, and medians of main collector roads. Street tree species for these streets are listed in the general species tables.

3.7.5.10 Plant stock

(2) For new street tree planting in subtropical boulevards in centre (SB1), city streets (CS1 and CS2) and locality streets, all trees are to be advanced stock material, with:

(a) street trees a minimum stock size of 200L and a minimum height of 3.5m;

(b) feature trees a minimum stock size of 200L and a minimum height of 5m when planted.

(3) All trees to have a minimum clear trunk of 1.8m measured from the top of the tree grate, porous paving or finished soil level where planted in garden beds or turf, to the lowest branch.

(4) For new street tree planting to all other streetscape types, the minimum stock size is 25L.

3.7.5.11 Implementation

(1) For all streetscape works tree planting other than tree planting for new roads, developers must undertake planting and maintenance.

(2) Where for new street tree planting on newly constructed roads, developers can either:

(a) contribute to the cost of planting and establishing street trees, with the amount calculated by a rate per 6m of allotment frontage that provides for 1 tree per allotment, planted by Council when the development is substantially built; or

(b) undertake their own tree planting and a 12-month maintenance period for stock sizes less than 45L, and 24-month maintenance period for stock sizes greater than 45L.

(3) A road reserve landscaping plan for newly constructed roads showing existing and proposed trees, location of street lights, driveways, services etc., should be submitted and approved (prior to planting) by Council. The minimum stock size, quality of plants, planting and after care should conform to Council requirements. Trees damaged or declined during the maintenance period or the duration of development, whichever is the longer, must be replaced.

(4) The following tables are a guide to species of trees, shrubs and ground covers that generally perform well and require minimal maintenance in roadside landscaping. These lists are deliberately not comprehensive as final species choices should be based on professional site condition analysis and advice from a suitably qualified landscape architect or horticulturist.

(5) Street tree species are generally small–medium crowned, upright or feature tree species from these tables.

(6) Outside of Locality Advice areas, street tree species must comply with the most up-to-date lists of Types of street trees on Council’s website.

3.7.5.17 Small trees or large shrubs

Small trees and large shrubs listed in Table 3.7.5.17.A are suitable for planting inside roundabouts and roadside build outs outside of the sightline-constrained parts of those sites.

Table 3.7.5.17.A—General species table for small trees and large shrubs

Scientific name

Common name

Syzygium “Aussie Compact”

Aussie compact

Syzygium “Aussie boomer”

Aussie boomer

Syzygium “Elite”

Elite

Melaleuca tamariscina var. irbyana

Broombrush

Callistemon sp.

Bottlebrush

Tristaniopsis laurina

Water gum

3.7.5.18 Low shrubs and other plants with sculptural forms

Low shrubs and other plants with sculptural forms listed in Table 3.7.5.18.A are suitable for planting as understorey plantings within garden areas of verges, roundabouts, medians or roadside build outs outside of sightline-constrained parts of those sites.

Table 3.7.5.18.A—General species table for low shrubs and other plants with sculptured form

Scientific name

Common name

Syzygium “Tiny Trev”

Tiny Trev

Doryanthes excelsa

Spear lily (setbacks required for flower spear maintenance)

Crinum pedunculatum

Swamp lily

Agave attenuatum

Agave

Dietes grandiflora

Wild iris

Strelitzia reginae

Bird of paradise

Agapanthus africanus

African lily

Cordyline rubra

Red palm lily

3.7.5.19 Small–medium shrubs

Small–medium shrubs listed in Table 3.7.5.19.A are suitable for planting as understorey in gardens within verges, inside roundabouts and roadside build outs outside of the sightline-constrained parts of all of those sites.

Table 3.7.5.19.A—General species table for small-medium shrubs

Scientific name

Common name

Baeckea virgata

Baekea

Callistemon pachyphyllus

Swamp bottle brush/red, green bottlebrush

Callistemon “Wildfire”

Wildfire bottlebrush

Abelia grandiflora

Glossy abelia

Melaleuca “Claret Tops”

Claret tops

Schefflera arboricola

Dwarf umbrella plant

3.7.5.20 Groundcovers

Groundcovers listed in Table 3.7.5.20.A are suitable as understorey plantings within garden areas of verges, roundabouts, medians or roadside build outs within sightline-constrained parts of those sites.

Table 3.7.5.20.A—General species table for ground covers

Scientific name

Common name

Cissus antarctica

Native grape

Myoporum ellipticum

Myoporum

Lomandra sp.

Lomandra (small growing species preferred)

Dianella sp.

Blue flax lily (use in mix with other tufting ground covers for longevity)

Gazania rigens

Gazania

Nandina domestica “Nana”

Scarlet bamboo

Juniperus confertus

Juniper or blue pine

Liriope “muscari” “Evergreen Giant”

Liriope

Liriope “Stripey White”

Liriope stripey white

Grevillea sp. (prostrate forms)

Prostrate grevillea

3.7.6 Design standards for street furniture

3.7.6.1 General

(1) Council’s furniture suite is to be used in all instances where street furniture is required in the verge.

(2) Council’s furniture suite is to be used to ensure that all furniture installed in the verge meets all relevant standards for accessibility and safety, is easy to clean and maintain, and is able to be sourced for replacement.

3.7.6.2 Locations

(1) Where required, furniture is located to minimise clutter and provided in locations that are conducive to use.

(2) Furniture is located in the zone at the rear of kerb, allowing for clear pedestrian flow.

(3) To avoid conflict with traffic, all furniture must be located a minimum of 750mm from the nominal face of the kerb. Additionally, adjacent items must be appropriately spaced, to allow for ease of movement between them, as shown in Figure 3.7.6.2a.

(2) Exceptions also include those localities within the streetscape locality advice section of this planning scheme policy, where furniture colour is already established. In these locations new furniture is required to match the existing.

(3) All stainless steel furniture is manufactured in 316 grade stainless steel, and finished with a No.4 finish, with surface roughness (Ra) to be less than 0.5 µm.

3.7.6.4 Fixing

(1) All items must be surface-mounted to allow for flexibility in the locations of furniture, ease of replacement and installation after completion of other civil works.

(2) Surface mounting bolts must penetrate directly through the concrete slab or through the unit paving and mortar bed (where relevant) into the concrete slab.

3.7.7.1 Pedestrian lighting

3.7.7.2 Up-lighting in verge

Up-lighting will not be permitted in the verge, except where it is required to illuminate public art located in the verge.

3.8 Heritage kerb

(1) Heritage kerb in Brisbane includes kerbs, crossovers, channel stones, margin stones or other stone features that are made from either Brisbane Tuff or granite.

(2) Where heritage kerbs exist they are to be retained as follows:

(a) retained in situ as part of any redevelopment;

(b) a conservation management plan is to be prepared and submitted to Council's City Architecture and Heritage Team;

(c) where works are being undertaken in close proximity to heritage stone kerbs, care is to be taken to ensure that new asphalt road surfaces are neatly finished beside adjoining stone surfaces;

(d) where they cannot be retained in their existing location due to changes through redevelopment proposals, they are to be removed, stored during construction and reinstated to the new kerb alignment.

(3) On the rare occasion where Council approves the permanent removal of heritage kerb, the heritage material is to be surrendered to Council for stockpiling for future use in key locations.

(4) Infill stone kerb may be required as follows:

(a) where a frontage has gaps in the stone kerbing, consult with Council's City Architecture and Heritage Team to agree if infill stone kerbs or pre-cast concrete kerbs are required;

(b) where infill stone kerbs are required, they are to match as closely as possible with the existing kerbs, in terms of colour, finish and proportions.

(5) For stone kerb joints:

(a) plain concrete mortar or concrete is to be used for repairs or infill work to stone kerbs;

(b) do not allow mortar or other adjoining materials to cover exposed faces of stone kerb;

(c) kerbstones are to be a minimum of 150mm above the adjoining channel.

(6) The supply of Brisbane Tuff is scarce and can be sourced as follows:

(a) the developer is to locate their own source of kerbs;

(b) in special circumstances, Council has very limited supplies, which may be made available for particular development;

(c) this infill work and supply of Brisbane Tuff is to be undertaken in consultation with Council's City Architecture and Heritage Team and the relevant regional Field Services Group;

(d) the cost of supply and installation will be the responsibility of the developer.

(7) New kerbs are as follows:

(a) all new works adjacent to stone kerbs are to be pre-cast concrete kerb units, 'vertical' 300mmx150mmx450mm unit lengths;

(b) Council does not require the use of concrete imitation stone kerb blocks.

(8) Stone kerbs are not to be used where they have not previously existed.

3.9 Wildlife movement solutions

Wildlife movement solutions are provided where identified in the Streetscape hierarchy overlay map. Table 3.9.4.A lists options for delivering wildlife movement solutions. These are applicable for minor and major roads as identified in the table.

3.9.1 Wildlife movement solutions infrastructure

(1) Wildlife movement solutions will be required to facilitate safe wildlife movement of terrestrial and aquatic species in the following circumstances:

(b) where development requires road widening to an existing road and the site is adjacent to a location requiring wildlife solution infrastructure.

(2) To be effective, the types of wildlife movement solutions infrastructure provided is to be based on a solid, evidence-based understanding of the ecological connectivity requirements for native fauna occurring, or likely to occur, in that part of the Biodiversity areas overlay. This is to be achieved through a comprehensive ecological assessment and a whole-of-development approach to the planning, design and implementation of wildlife movement solutions. Guidance on undertaking an ecological assessment is provided in the Biodiversity areas planning scheme policy.

3.9.2 Locating wildlife movement solutions

(1) Wildlife movement solutions are to be located at sites that directly connect or re-connect components of the Biodiversity areas overlay.

(c) adopting designs known to be used by native fauna groups or particular fauna species, especially significant fauna species.

3.9.3.1 Major roads

Wildlife movement solution infrastructure for a major road will generally include a range of measures provided within a clustered location. It is expected that a major road in a biodiversity area will also incorporate a broad suite of wildlife movement infrastructure to cater for a range of fauna groups or species, as this maximises the effectiveness of the infrastructure provision in a cost-effective manner.

3.9.3.2 Minor roads

(1) A wildlife movement solution for a minor road will be designed for specific fauna species. It is not expected that a minor road would incorporate large-scale wildlife movement solutions infrastructure such as land bridges. A minor road requires smaller scale wildlife movement solutions such as culverts and maintaining canopy connectivity.

(2) Table 3.9.4.A provides a list of potential wildlife movement solutions including a description and illustration of the measure. This table also provides guidance on which options are suited to use on a major road, a minor road, or both. Further guidance on wildlife movement solution options can be sourced from the Queensland Government's two-volume manual 'Fauna sensitive road design' on the Department of Transport and Main Roads website.

(3) For road exclusion fencing and other safe movement solutions for the koala, guidance should be sought in the first instance from the Queensland Government's Koala-sensitive Design Guideline: A guide to koala-sensitive design measures for planning and development activities, available under Koala legislation and policy.

(4) A number of wildlife movement infrastructure solutions within Brisbane have been subject to monitoring by independent research bodies from Australian universities. The findings of these studies are being progressively published and provide an invaluable insight into the effectiveness of a range of measures for local native wildlife and should be considered, where available.

(5) In addition, the science of safe fauna movement using wildlife movement solutions infrastructure is an evolving field of study. A literature review to identify contemporary findings on newly trialled and effective wildlife movement solutions infrastructure could also prove worthwhile.

3.9.4 Identifying target species

(1) The Queensland Government and Brisbane City Council hold wildlife records and these should be accessed to identify fauna known to occur, or likely to occur in a particular locality. The significant fauna species listed in Table 8.2.4.3.D of the Biodiversity areas overlay code should also be reviewed to identify or 'shortlist' the possible species to inform the nature and location of wildlife movement solutions infrastructure. Significant fauna species that move predominantly along the ground, glide or swim should be considered important target species.

(2) A roadkill survey conducted as part of the ecological assessment may also assist in identifying target species.

Table 3.9.4.A—Wildlife movement solutions

Title

Description

Indicative suitability for road type:

Overpass

Land bridge

A land bridge is:

(a) a bridge extending over a road;

(b) covered in soil, planted with locally occurring native vegetation and enhanced with other habitat features (e.g. logs, rocks);

(c) also known as a wildlife bridge;

(d) may also support poles and other wildlife movement solutions.

Major roads

Cut- and-cover tunnel

A cut-and-cover tunnel occurs where the road passes below ground level through a tunnel with the area above available for revegetation and other wildlife movement solutions such as those adapted on land bridges.

Major roads

Canopy bridge

A canopy bridge is:

(a) a single rope crossing, rope tunnel, rope ladder or pole suspended above the traffic either from vertical poles or from trees;

(b) used by arboreal and climbing fauna species such as gliders and possums.

Major and minor roads

Pole

A pole is vertical and may be placed in the centre median, on the road verge or on a land bridge to provide species that glide with intermediate landing and multiple launch opportunities.

Major and minor roads

Underpass

Culvert

A culvert:

(a) is a square, rectangular or half circle shape and may be purpose built for fauna passage or water drainage, or a combination of both;

(b) is typically pre-cast concrete cells or arches made of steel;

(c) varies in size depending on the target species;

(d) where water conveyance is involved, it includes bridges and furniture such as logs, rocks, shelving, ledges, ramps and railings that remain dry.

Major and minor roads

Tunnel

A dry tunnel is a typically round pipe of relatively small diameter (e.g. less than 1.5m in diameter)

Major and minor roads

Passage below bridge

A passage below bridge:

(a) is a structure that maintains the grade of the road or elevates the traffic above the surrounding land, allowing fauna to pass under the road; facilitates water drainage or movement of local human traffic and secondarily facilitates fauna passage;

(b) has minimal vegetation clearing (clearing only required for bridge piers or pylons) and allows natural vegetation to grow under infrastructure.

Major and minor roads

Non-structural mitigation

Canopy connectivity

Canopy connectivity is achieved by the linear clearing being kept sufficiently narrow to allow the tree canopy to remain continuous above the road, or sufficiently narrow where discontinuous to allow fauna species such as gliders to safely traverse.

Minor roads

Local traffic management

Local traffic management involves devices to reduce the speed or volume of traffic or increase driver awareness of fauna (e.g. road closures, chicanes, crosswalks and signage).

Exclusion fencing stops fauna crossing the road surface, and is used as an integral component in encouraging fauna towards safe crossing passage (such as an overpass or culvert).

Major and minor roads

Fauna-friendly fencing

Fauna-friendly fencing allows fauna (e.g. kangaroos, wallabies, koalas) to easily move through or under a fence, and may be appropriate in some cases to allow fauna movement at key locations on low volume traffic roads. It can be used in conjunction with exclusion fencing to direct fauna through the landscape.

Nest boxes provide replacement refugia, nesting and roosting opportunities for fauna when tree hollows are removed. The type of nest box design selected is dependent on the fauna species being catered for.

Major and minor roads

Shelter site

Shelter sites have natural or non-natural materials placed within the road corridor or adjacent areas to restore or replace lost habitat (e.g. logs, local rocks or recycled terracotta roof tiles).

Major and minor roads

3.10 Traffic management and direction

3.10.1 General

3.10.1.1 Pavement marking

(1) Pavement marking designs should be prepared in accordance with the Queensland Manual of Uniform Traffic Control Devices (MUTCD, Queensland Department of Transport and Main Roads) and the specific requirements of Brisbane City Council Standard Drawings and Reference Specification for Civil Engineering Works S155 Road Pavement Markings. This specification details the acceptable materials and defines the requirements for the installation of longitudinal and transverse pavement markings including retroreflective glass beads and anti-skid material.

3.10.1.2 Traffic signs

(1) Traffic signs should be provided in accordance with the Queensland Manual of Uniform Traffic Control Devices (MUTCD, Queensland Department of Transport and Main Roads) and the specific requirements of Reference Specification for Civil Engineering Works S154 Traffic Signs and Roadside Furniture.

Editor’s note—Guidance on directional and way-finding signage and pavement marking design can be found in Brisbane City Council Bikeway & Greenway Signage Manual.

Editor’s note—Guidance on directional and way-finding signage and pavement marking designs for pathways associated with the Moreton Bay Cycleway can be found in the Moreton Bay Cycleway Signage Manual.

3.10.3 Coloured pavement treatment

3.10.3.1 General

(1) Coloured or decorative pavement surface treatments and markings are used to alert road users to a different or modified driving environment or the presence of other traffic control measures requiring extra caution.

(2) These treatments and markings are normally a screeded or sprayed surface treatment applied over the existing road surface, stencilled/patterned or coloured concrete or pavers/bricks.

Note—Aggregates used in coloured treatments are to be clean, dry, hard, tough, durable, moderately sharp grains of either natural stone or calcined bauxite. Other aggregate materials (e.g. crushed glass) are not included in the material specification for use by Council and are not to be used on Council-controlled roads or infrastructure.

(1) The correct usage of threshold treatments is to designate a changed road environment where arterial or sub-arterial roads (typically 60km/h or greater) intersect neighbourhood or local access roads (50km/h or less). The intent is to highlight a change of speed limit or road function, that is, movement vs. access. The treatment for the entrance to a LATM consists of a threshold treatment (typically full width of road) of red with a yellow border.

(2) Coloured pavement treatments are also used to delineate the path through a traffic management or calming device. These treatments are the same as used for a threshold treatment, namely red with a yellow border.

3.10.3.5 Bicycle lanes

(1) Coloured bicycle lanes are typically used to delineate specialist bicycle facilities and lanes on the road pavement. They serve to restrict access where there are high levels of interaction between bicycles and other road users, typically at intersections. Coloured bicycle lanes are green.

(2) Associated longitudinal and transverse pavement marking types and dimensions are shown in the Queensland Manual of Uniform Traffic Control Devices (MUTCD, Queensland Department of Transport and Main Roads) and the specific requirements of Council’s Standard Drawings

(3) For typical longitudinal traffic markings, waterborne paint is preferred if the thickness tolerance for long-life material cannot be achieved.

(4) A long-life material (other than hot applied thermoplastic) may be used on high volume roads where excessive wear may occur. Any markings in a long-life material are not to exceed 3mm in thickness. Hot applied thermoplastic markings are to be avoided in areas with high bicycle use, particularly when used for bicycle lanes.

(5) Testing has shown that hot applied thermoplastic can be hazardous to bicycles (and motorcycles) due to the potential for water build-up or ponding behind the line which has the potential to contribute to aquaplaning and lower skid-resistance on the surface of the material if an anti-skid material is not applied at installation.

3.10.3.6 School zone enhancements

School Zone Enhancements (SEZ) markings are installed to alert motorist that they are entering a specialist traffic zone. The SEZ consists of a threshold treatment (either part or full width of road) of red with a yellow border with the legend ‘SCHOOL ZONE’ written in white across the red section of the threshold.

3.10.3.7 Pedestrian facilities

(1) A coloured pavement surface marking maybe used at pedestrian facilities to show a clear path or delineation for users. These facilities include pedestrian refuges and pedestrian buildouts at crossings.

(2) Coloured pavement markings may also be installed to highlight or provide a contrast for pedestrian facilities, for example, a zebra crossing.

3.10.3.8 High friction surface treatments

This treatment is applied to areas or sections of a road that has a history of accidents and/or considered to have a surface with an unacceptable skid level.

While not technically a coloured pavement treatment and not performing a traffic function, these treatments are normally a different colour to the existing road surface and are often very noticeable. They are covered by the same specification as coloured pavement treatments and are often applied by the same suppliers using very similar techniques.

Care has to be taken when considering work on or near these treatments as their installation is considered a safety issue. When maintenance is required on these treatments, they must be replaced with a high fiction surface treatment that has a minimum skid resistance value of 65 BPN. Refer to Reference Specification for Civil Engineering Works S155 Road Pavement Markings for material details.

3.11 Fences and barriers

3.11.1 General

(1) Fences and roadside and safety barriers systems are planned, designed and constructed in accordance with the current edition of the following standards:

(d) Queensland Department of Transport and Main Roads Manual of Uniform Traffic Control Devices (MUTCD);

(e) Queensland Department of Transport and Main Roads Standard Drawings;

(f) Queensland Department of Transport and Main Roads – Road Safety Barrier Systems, End Treatments and Other Related Road Safety Devices (Assessed as Accepted For Use on State-Controlled Roads in Queensland);

(g) Brisbane City Council Standard Drawings.

(2) Fences and roadside and safety barriers are provided for:

(a) Protection of vehicles and occupants from roadside hazards such as embankments, rigid objects, etc.;

(4) Road Safety Barriers work on one of two principles – they will either deflect or redirect vehicles away from the hazard or will stop the vehicle outright. Where a system is designed to stop a vehicle outright, energy absorption capability characteristics should be included in the design to minimise or reduce the potential injury that maybe suffered by the occupants of the vehicle.

3.11.2.4 Other barriers

(1) These barrier systems are generally used for vehicle and pedestrian hazard identification and delineation and are utilised as a visual barrier, rather than a physical barrier.

(3) These systems may restrain or stop vehicle and/or pedestrian movement, but not both.

(4) Systems are typically installed as a low-impact solution and will often minimise the visual impact at a location.

3.11.2.5 Temporary barrier systems

Temporary barrier systems are used to provide positive protection for workers and the public. These barrier systems are installed on a site by site basis and are designed to comply with the requirements in the MUTCD for work sites.

3.11.3 Design standards

3.11.3.1 Fences

(1) The minimum standard of pedestrian safety fence is the galvanised tubular handrail as shown on Standard Drawing BSD-7001

(3) A galvanised tubular handrail with chainwire (Standard Drawing BSD-7001) or a galvanised weld mesh fencing (Standard Drawing BSD-7002) should be provided where there is a danger of children gaining access to high risk areas or where the drop height exceeds 1 m.

(4) A powder coated steel fence (hunter rod top or approved equivalent, capable of sustaining the imposed actions specified in AS 1170) should be installed. where the drop height exceeds 1.5 m.

(5) Where required, a log barrier fence including a lock rail for access should be provided in accordance with Standard Drawings BSD-7012, BSD-7051 and BSD-7054.

(6) The fencing should not hinder general maintenance, otherwise the fencing should incorporate vehicular access gates or the fencing panels are designed for easy removal. Pedestrian gates should be provided along road frontages.

(7) A concrete (extruded or cast in situ) mowing strip should be provided under all fences (including acoustic barriers) which interface with lawn and landscaped areas. A minimum 140 mm wide x 100 mm deep strip, flush with the surrounding ground, will need to be installed under timber fences/walls or galvanised steel fences. Mowing strips are generally not required under masonry or concrete fences/walls as the footings are usually sufficient for this purpose.

3.11.3.1.1 Hydraulic constraints

(1) It is desirable that fencing is not erected inside any drainage easement or overland flow path or flood regulation line or waterway corridor. Council recommends against the construction of debris retaining or solid fences, as these structures will inhibit the conveyance of floodwaters. However in instances where the overland flow between private allotments is shallow, generally less than 200 mm deep, solid fences can be constructed provided that openings are installed at ground level to accommodate overland flows.

(2) Council approval is required where fencing is proposed inside any drainage easement or overland flow path or flood regulation line or waterway corridor. Some suggested fencing styles include:

(a) Open post and rail, where no panels of fencing are incorporated between the post and rail structure to provide minimum resistance to flood flows. Examples include log barrier fencing and galvanised tubular handrail;

(b) Collapsible fencing are designed to collapse under flood loading so not to increase flood levels, but are also anchored to avoid being washed away. Low strength ties may be used to hold the fence in place during non-flood times;

(c) Swing fencing are designed to yield under the pressure of flood flows so as not to increase flood levels, but are also anchored to avoid being washed away. Usually fence panels are fitted with hinges or pivot points to allow opening during floods. Low strength ties may be used to hold the fence in place during non-flood times;

(d) Lifting fencing are designed to be temporarily raised to not to obstruct flood flows.

3.11.3.1.2 Fence types and typical applications

Table 3.11.3.1.2.A—Fence types and typical applications

Fence Type

Application

Benefits

Design considerations

Two Rail, Post and Rail Fence

Pedestrian Protection from slopes etc.

Highly visible (with appropriate delineators);

Low visual impact

Hazard to users if installed too close to roadway.

Easily climbed.

Traffic delineation along split level roadways – not preferred use.

Highly visible;

Cost effective to construct.

End treatment is spear hazard to vehicles

Will not restrain errant vehicle

Galvanised Tubular Handrail

Pedestrian protection / guidance on footpaths etc.

Strong fence, not easily damaged;

Good use for function, especially fences with mesh.

Hazard to users if installed too close to roadway.

Can be climbed over/through (no mesh).

Traffic delineation along split level roadways

None

End treatment is spear hazard to vehicles

Low visibility

Welded Mesh Fencing

Pedestrian protection / guidance on footpaths, traffic islands etc.

Good use for function.

Can have low visibility – requires appropriate colour and delineators;

Easily damaged by vehicle strike.

Pedestrian Safety Fencing

Pedestrian protection / guidance on footpaths, traffic islands etc.

Strong fence, not easily damaged by pedestrian activity;

Good use for function.

Risk of spear hazard from top rail;

Can have low visibility – requires appropriate colour and delineators

Easily damaged by vehicle strike.

3.11.3.2 Acoustic fences

(1) The construction standards of typical 2 m high timber acoustic fence are shown on Standard Drawings BSD-7021 and BSD-7021. These drawings do not represent suitable noise attenuation solutions for all developments.

(2) A site specific attenuation solution for each development should be determined in accordance with the attenuation criteria and methodologies set out in the Noise Impact Assessment Planning Scheme Policy.

3.11.3.3 Road safety barriers

(1) Road Safety Barriers solutions or products must have sufficient technical/safety approvals demonstrating that the product has been tested to appropriate levels/standards (e.g. American NCHRP Test Level 2 or Test Level 3) or the product conforms to QTMR or Australian Standards.

Table 3.11.3.3.A—Road safety barrier types and applications

Barrier Type

Application

Benefits

Design considerations

Concrete Barrier#

Typically highway and high-speed areas, where total vehicle restraint is required

Very effective in stopping errant vehicles

Expensive to construct;

Visually unappealing.

Guardrail

As for concrete barriers, especially in unkerbed areas where angle of impact is likely to be acute (<10⁰)

Very effective in stopping errant vehicles;

Lower cost than concrete barrier;

Can be used back to back.

Requires large clear space behind barrier;

Inappropriate terminal ends pose spearing hazards;

Ineffective if used in short lengths (<30m).

Bridge Barrier

As per concrete barrier

Very effective in stopping errant vehicles;

Often only solution in locations with limited space or on bridges and other structures.

Expensive to install and maintain;

Inappropriate terminal ends pose severe crash hazard

Wire Rope Barriers

As per guardrail

Very effective in stopping errant vehicles;

Lower maintenance cost than guardrail;

Low visual impact;

Suitable for use on embankments as ramping does not occur.

Requires large clear space behind barrier;

Requires a minimum radius to be effective (i.e. not suitable on small radii);

#Type-F concrete barriers are only acceptable for use on roads with speed limits of 80 km/h or less

3.11.3.3.1 Flexible guardrail – general requirements

(1) Flexible guardrails are not generally suited to urban situations.

(2) Flexible guardrails should be designed as per Reference Specification for Civil Engineering S154 Traffic Signs and Roadside Furniture and QTMR Standard Drawings

(3) Flexible guardrails should be provided at locations where the consequences of a vehicle leaving the road pavement would be worse than the vehicle hitting the guardrail. These locations would generally include:

(a) At steep (>1:4) road embankments.

(b) At roadside obstacles.

(c) At structures, i.e. bridges and culverts.

(d) At sudden narrowing of road pavement in addition to the use of hazard markers.